Internally ribbed manifold for multicylinder internal-combustion engines



Feb. 26, 1952 M|| BRATH 2,587,360

INTERNALLIYNRIBBED MA NIFOLD FOR MULTICYLINDER TERNAL-C USTION ENGINES Filed b. 16, 1949 INVENTOR. ARTHUR F. MILBRATH lm 10am Wm HTTORIYEY5.

Patented Feb. 26, 1952 INTERNALLY RIBBED I MANIFOLD FOR. MULTICYLINDER INTERNAIi-C'OMBUS- TIONI ENGINES Arthur F. Milbrath, Milwaukee wisg assignor to Wisconsin Motor. Corporation,.Milwaukee,, Wisi, a. corporation of Wisconsin.

Application February 16, 1949; Serial No. 7?;022

invention relatesto an internally ribbed manifold for multi-cylinder internal combustion engines.

It i's'an object of the invention to render combustion in theseveral cylinders more uniform, regardless of engine speed, by effecting amore uniform distribution of the combustible mixture as between the several cylinders throughout the range of engine speeds, and even tomake-possible uniformcombustion of lowergrade fuel oils than can be employed without the benefit of the present invention.

The invention can best be explained by reference to the accompanying drawings, wherein:

Fig. 1- i's'a view in end elevation of a V-type engine equippedwith a manifold embodying the invention, portions of one of the cylinder blocks and certain of the manifold passages beingbroken away.

Fig; 2 is a; viewinl'ongitudinalsection through a; manifold embodying the invention.

v Fig; 3 is a detail view taken incross section on the line-3-3 ofFig. 2-. Fig. 4 is-aninverted plan view of the manifold shown in Fig; 1 and Fig. 2'.

Fig. 5 is a fragmentary detail view of a modifled embodiment of the invention as it appears in a longitudinal.crosssection through the manifold or conduit, the ribs being shown in plan.

The engine which has been equipped for the purpose of exemplification with a manifold embodying the invention, happens to be a V-type, four-cylinder engine having angularly divergent cylinder blocks 6 and 'i'. The manifold. distributi'ng, ducts 8 and 9 respectively lead to the cylinders, and the exhaust' gas collecting; ducts In and ll'ope'n therefrom in accordancewith conventional practice. While the present invention'is' not concerned specifically with the exhaust arrangements, it may be noted that the intake manifold I2 and the exhaust manifold l3 may conveniently be cast in one piece as is best shown in Figs. 2-and 3. The carburetor I5 is connected centrally to the intake manifold l2 by means of the coupling flange 16. The ex-.- haust manifold I3 is tapped at I! to receive the exhaust pipe Ill.

The particular carburetion shown involves the use of an updraft carburetor, but the invention is by no means limited thereto. In any instance where the carbureted air must be divided, as between the manifold branches l9 and 20, lead.- ing to the respective cylinder blocks, it has been noted that there is considerable irregularity of flow. The turbulence within the manifold fluctuates in. accordance. with the speed, and the grade of fuel and, frequently, independently of either of these factors; In consequence, uneatom-ized and unvaporized. droplets of fuel such sis-commonl are found clinging to and advancing along the manifold wall,.. whenever they are acted upon by air currents sufdciently strong to move them,may,.as aresultiof erratic turbulence, be thrown at one time: principally into one of the. manifold branches, and at. another time principally into a different: manifoldbranch, overloading firstone cylinder, and then. the. other,,. and making impossible any correct adjustmentof the carburetor which. will keep: the cylindersfiring equallyand with uniformity.

What has: been said with regard to. the. pro-. pulsi'on of. unatomized droplets of fuel is. alsotrue of. the heavy ends. of thefuel vapors which, evemthough: they. be free. of the walls,. are. caused by erratic turbulence. to flow one way or the. other into one or other of. the manifold branches in such fashion as has heretofore defied any attempt at control.

I have found that erratic turbulence.- can be almost" entirely controlled through. the use of vanes which desirablytake the form of ribs cast internally on the manifold wall. These vanes give definite direction to the currents of carburete'd air and, being located onthe wallsurfa'ce,

they tend to provide well-defined accelerated.

currents of air flow which pick up: andmove with substantial; regularit the droplets whose movement has heretofore. defied regulation. In ac-- cordance: with the preferred practice of; the invention, I locate these vanes at the point where theair supplied by' the carburetor t5 isdivided' between the manifold branches ['9 andlll: Thus.

one of the. vanes- Zlr, located. on. the. far wall of:

the manifoldas: viewed. in. Fig; 2, commenceslat the manifold inlet and curves arcuately along the far wall toward the manifold branch 20. The other vane 22, located on the near wall of the manifold as viewed in Fig. 2 (only a fragment of such wall being there illustrated), begins at the same point and, directly opposite the curved vane 2|, curves toward the manifold branch l9.

While the disposition of these vanes at this particular point where the manifold branches is a preferred practice, it is also possible either to use additional vanes, or to locate the vanes in a straight length of manifold passage, both of these features being illustrated in Fig. 5, where a straight length of manifold passage is shown at 23 with helical vanes 24 and 25 on one side of the passage, and helical vanes 26 and 21 on the opposite side of the passage. In this view, the vanes or ribs have been exposed by cutting away the top half of the manifold to expose the vanes. It will be noted that each of the vanes runs out or tapers to merge with the wall of the manifold at its ends, reaching maximum thickness intermediate its ends.

It is believed that in the straight wall passage, the action of the ribs or vanes is slightly different from that produced where they are located at the point of air division. In both instances, it appears that the vanes pick up and concentrate droplets which are being propelled by the air currents along the inner wall of the manifold, the vanes also concentrating in the angle between the vane and the manifold air currents which give a sufficient impulse to the droplets or stream of fuel, either to complete the atomization or vaporization thereof, or to entrain them for more rapid and more uniform movement to the cylinder for combustion. In the use of the vanes in Figs. 1 to 4, the vanes have the additional advantage that their curved form and symmetrical disposition tend to divide the charge more uniformly, assuring the delivery of half of the charge into one branch of the manifold, and the other half in the other with considerable uniformity and regularity, regardless of engine speed. In any event, tests as to uniformity .of combustion, supplemented by visual inspection of mixture flow through manifolds with transparent walls, have indicated that with the vanes there is substantial uniformity at all speeds, whereas, without the vanes, there is erratic turbulence with particular variation when engine speed varies. It has also been demonstrated that an engine which will operate satisfactorily only with a good grade of gasoline when its manifold is not equipped with the vanes or ribs here disclosed, can be made to operate with equal or greater satisfaction on No. 2 furnace oil when the manifolds are ribbed or vaned interiorly in accordance with the present invention.

' I claim:

1. As a new article of manufacture, an internal combustion engine manifold comprising a tube having opposed wall surfaces and opposed series of internally projecting ribs along said opposed wall surfaces, each such rib extending helically along the. wall of the manifold for less than a full circumference of the tube.

2. As a new article of manufacture, an internal combustion engine manifold comprising a tube havin substantially uniform cross section and provided interiorly with a plurality of internally projecting ribs each comprising a curved protuberance extending helically along a wall of the manifold for less than a full circumference of the tube, each rib having maximum thickness intermediate its ends and tapering towards its ends.

3. As a new article of manufacture, an engine manifold which comprises a conduit interiorly provided with ribs axially inclined said ribs being discontinuous and converging toward and merging with the contours of the interior of the manifold at both ends of the respective ribs.

4. As a new article of manufacture, an engine manifold which comprises a conduit interiorly provided with discontinuous ribs axially inclined and merging at spaced intervals with the contours of the interior of the manifold and symmetrically disposed in opposite sides of the conduit.

5. A manifold as defined in claim 4 in which the manifold conduit comprises an inlet and a pair of branches having a juncture at the inlet, the ribs being disposed adjacent the said juncture and oppositely inclined toward the respective branches.

6. As a new article of manufacture, an internal combustion engine manifold comprising integrally an inlet and a pair of oppositely extending branches, the inlet having opposing walls between which the branches open, and the said walls being integrally provided with arcuately curved and mutually opposite ribs respectively curving toward different branches.

. 7. A manifold comprising a conduit integrally provided on opposite walls with opposed multiple ribs of generally helical discontinuous form.

8. The manifold of claim 7 in which the ribs have maximum thickness intermediate their ends and merge with the conduit at such ends. I

9. As a new article of manufacture, an internal combustion engine manifold comprising an inlet and a pair of balanced oppositely extending branches, each of said branches being provided with an equal number of service connections to an equal number of cylinders, a plurality of riblike protuberances each extending inwardly from the walls of the inlet, one of said protuberances extending into one of the branches, and another extending into another branch whereby to divide gaseous flow from the inlet to the respective branches.

ARTHUR F. MILBRATH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

